Yes vote unbeatable 'unless a lot of people are straight out lying'

People attend the Pride Festival Rally held in Brisbane on Saturday, September 23, 2017. Thousands of people are expected to march through Brisbane as part of the annual Pride Festival Rally as the deadline for the marriage equality survey approaches. (AAP Image/Regi Varghese) NO ARCHIVING

Australians appear to be unmoved by anti-same-sex marriage warnings of creeping gender ideology, social destruction, or sexual confusion, with the case for change surging ahead.

With more than a month to go in the government's controversial postal survey, an aggregation of public polling and some recent unpublished research shows the "yes" case for legalising same-sex marriage has maintained its strong lead among ordinary voters.

This is despite the attempts by opponents to introduce other issues such as the Safe Schools program, the rights of children, and a diffuse complaint about increasing political correctness.

Respected pollster John Stirton has crunched the numbers based on published polls and concluded that with a majority of votes already cast, the race appears to be all but decided.

"It's very hard to see how the 'no' case could win from here unless an awful lot of people are straight-out lying to pollsters," he said.

Formerly a pollster with Fairfax/Nielsen for 17 years, Mr Stirton analysed polls published between August 1, a week before the survey was announced, and October 2.

He said there were some difficulties with cross-poll comparisons and inconsistencies created when polls changed their questions from survey-to-survey but the trend appeared to be pretty clear.

Mr Stirton said public support for marriage equality when all polls are combined - and excluding "did not know" - was running at above 65 per cent. By contrast, support for the "no" case was running at below 35 per cent.

With several polls now showing the "yes" vote with a resounding lead, the Equality Campaign has cautioned against complacency. Both sides have stressed there are millions more votes still up for grabs, and the two camps have vowed to campaign fiercely until the final day.

"We're going to campaign until the very last minute because it's simply too important for us not to," Equality Campaign director Tiernan Brady said. "You can't expect someone else to get this over the line - everybody has to vote."

Coalition for Marriage spokesman Lyle Shelton told supporters on Tuesday: "We need to keep going because there are still millions of votes to win."